Add error checking to catch my silly coding mistakes

refs #1880
First attempt at separating model camera from view camera

This is a work in progress.  It does not work in its current state:
Stores objects' transform in the threejs.js model driver so the view can change the value stored inside the renderer itself w/o polluting the model w/ user-specific values - refs #1880
Adds a viewTransform property to nodes that implement the "navigable" behavior so they can move that object independent of the model - refs #1955
Adds a controlNavObject function in the threejs.js view driver to allow a user to take control of a navigable object - refs #1956
Adds a findNavObject function in the threejs.js view drive that is called when a user joins and determines which navigable object the user should control - refs #1957
Fix typo in multiuser/index.vwf.html - "ration" should be "ratio"

refs #1879